Wheel dresser



Mite States [72] Inventor Henry F. Swenson 22 Homehill Lane, Roseland, New Jersey 07068 x [211 App]. No. 713,881 [22] Filed March 18, 1968 [45] Patented Oct. 6, 1970 [54] WHEEL DRESSER 12 Claims, 12 Drawing Figs.

[52] U.S.Cl 125/11 [51] Int. Cl B241) 53/00 [50] FieldofSearch 125/11,39

[56] References Cited UNITED STATES PATENTS 2,366,623 1/1945 Jak0bsen..; 125/11 2,400,825 5/1946 Jakobsen I 125/11 2,458,859 1/1949 Kestell 125/11X 2,853,994 9/1958 Ronches 125/11 Primary Examiner-Harold D. Whitehead AtlorneyRalph R. Roberts ABSTRACT: A wheel or tool dresser for precisely shaping grinding wheels with arcuate and angle shapes is provided with stops which may be set to precise limits to dress the wheel at determined angles. The dresser includes a base which carries nested upper and lower swivel rings and a brake or drag disposed to engage the inner surface of the lower ring. The pedestal is rotatably supported on a plurality of balls and may include sliding surfaces with cam portions which compensate for the arc of swing of the dressing point. A vibration dampening member in the form of a spring supported weight may be provided in the pedestal. The upper and lower swivel rings are clamped by means of a thumb screw and include stops which are engaged by adjustable screws carried bythe pedestal, the adjusting of the screws providing a precise setting of the displacement of the pedestal.

Patented Oct. 6, 1970 v 3,532,084

IN VENTOR.

HE/VRX F Swavsozv BY Patented Oct. 6,1970 3,532,084

Sheet 3 ,of 5

, INVENTOR. 1 HENRY F SWENSON' I BY A GENT.

WHEEL DRESSER BACKGROUND OF THE INVENTION 1. Field of the Invention The field of art to which this invention pertains is found generally in the class of Stone Working and in particular in the subclass of Grinding-wheel dressing". Also pertinent is the subclass of Tools-surface traversing" and the additional dependent subclass ofDiamond" tools.

2. Description of the Prior Art The contour dressing and shaping of grinding stones is often done by a diamond dressing point and the like in which the diamond is carried in a pedestal which is rotatable around a pin carried by a base. In addition, the pedestal usually is provided with a pivoted upper portion by which the diamond is swung in an arc to define a plane. In the known devices employing this construction, the pedestal often will vibrate under the duress of shaping the wheel. In addition, a precision positi'oning of the dresser point and the plane or are of movement of the point is required to shape the wheel for use in todays machining processes. Setting stops are customarily used to provide the angle positioning. These stops are usually located on movable members who are easily moved except when locked. The accurate setting and locking is rather difficult and leads to inaccuracies.

In certain dresser mechanisms it is desirable that a compensation be provided for the fall away" of the dresser point as it is moved through an arc. Prior to the present invention this compensation, when made, is made by adjusting the mechanism. This requires calculation by the user and deft manipulation of the apparatus.

The wheel dresser of this invention is an improved control mechanism for dressing grinding wheels as shown in the patents to Jacobsen, Ser. Nos. 2,400,825 and 2,366,623. In these and other dresser mechanisms there is need for more accurate and diversified use. In particular, it is desirable to be able to dress stones with accuracy, to provide both convex and concave radius and to form precise angles. In the improved embodiments, hereinafter shown and described, the wheel dresser of this invention provides a solution to these problems.

SUMMARY OF THE INVENTION A wheel dresser for shaping grinding wheels and the like includes a pedestal rotatably carried upon a base by a plurality of balls. Rotatable with the pedestal is a stop pin having adjustable screws disposed so as to engage stops extending from upper and lower swivel rings. A brake or drag is disposed in the base so as to engage the lower swivel ring to retain the ring at its moved position while the upper ring is engaged by the stop pin for movement in the other direction to a determined position. A clamping shoe is adapted to engage both swivel rings and retain the rings in their set position. A vibration dampener in the form of a spring-supported weight in certain embodiments of the invention is carried in the pedestal. The sliding surfaces of the pedestal members may be shaped to provide cammed movements for compensation of the arc movement of the tool dressing point.

It is an object of this invention to provide a wheel dresser wherein a pedestal member is supported on a plurality of balls and is spring biased toward the balls by determined tension, the pedestal including a swivel plate rotatably carried by a base. A precise positioning of the pedestal is provided by the selectable setting of adjusting screws carried in a stop pin, the ends of the screws disposed to engage stops carried on upper and lower swivel rings. A clamping screw is disposed to engage the rings to lock the rings in the selected position on the base.

It is a further object to provide a wheel dresser wherein the pedestal may include a spring suspended weight disposed so as to provide a vibration dampener.

It is a further object to provide a wheel dresser wherein the pedestal has sliding surfaces contoured to provide a cam action for compensating the arc of movement of the tool dressing point.

INTENT OF THE DISCLOSURE Although the following disclosure offered for public dissemination is detailed to insure adequacy and aid in understanding of the invention, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how it may later be disguised by variations in form or additions of further improvements. The claims at the end hereof are intended as the chief aid toward this purpose, as it is these that meet the requirement of pointing out the parts, improvements or combinations or methods in which the inventive concepts are found.

There has been chosen a specific embodiment of the wheel dresser and an alternate construction thereof, each carrying a dressing point for use in dressing grinding stones and the like and showing in their constructions a preferred means for precisely regulating the dressing action of the point. This specific embodiment and the alternate embodiment thereof have been chosen for the purposes of illustration and description as shown in the accompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 represents an isometric view of a preferred embodiment ofa wheel dresser ofthis invention;

FIG. 2 represents a side view of the tool dresser of FIG. 1 with substantial portions of the view in section to show the internal construction of the tool dresser;

FIG. 3 represents a plan view looking downwardly on the line 3-3 of the tool dresser of FIG. 1;

FIG. 4 represents an exploded isometric view of a pair of mating movable upper and lower swivel rings each provided with a stop pin associated in the defining of the angular setting of the pedestal of the dresser;

FIG. 5 represents an enlarged sectional view through the pedestal portion of the dresser and showing a cam arrangement providing compensation for the arc of movement of the dressing stone, the view being taken on the line 5-5 of FIG. 2;

FIG. 6 represents a sectional side view of an alternate wheel dresser having certain construction features which are different from the dresser of FIG. 2;

FIG. 7 represents an isometric view of the stop pin and the retained adjusting screws, the view looking in the direction of the arrows 7-7 of FIG. 6;

FIG. 8 represents a rear view of the tool dresser of FIG. 6, the view taken on the line 8-8 of FIG. 6;

FIG. 9 represents a plan view of the face of a pedestal member and showing a compensating cam formed thereon, the view taken on the line 9-9 of FIG. 10;

FIG. 10 represents a fragmentary sectional view through the pedestal of the tool dresser of FIG. 6 and showing an alternate cam arrangement for compensating for the arc of movement of the dressing point;

FIG. 11 represents the sectional view of the view of FIG. 10 but with the pivoted pedestal portion moved to one limit of swing, and

FIG. 12 represents the sectional view of the view of FIG. 10 but with the pivoted pedestal portion moved to the other limit of swing.

In the following description and in the claims, various details will be identified by specific names for convenience. The names, however, are intended to be generic in their application. Corresponding reference characters refer to like members throughout the several FIGS. of the drawings.

The drawings accompanying, and forming part of, this specification disclose certain details of construction for the purpose of explanation of the broader aspects of the invention, but it should be understood that structural details may be modified in various respects without departure from the concept and principles of the invention and that the invention may be incorporated in other structural forms than shown.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1, 2 and 3, there is shown a wheel dressing apparatus of the type used particularly for dressing rotary grinding wheels. This apparatus includes a base disposed for attachment to the table of a grinder or the like (not shown). This table may have a clamping means or a magnetic chuck by which the dresser is held in a determined relationship to the wheel of the grinder. Carried on the upper portion of the base is a dovetail slide or cover plate 22 constructed so as to be retained and reciprocably moved in complimentary dovetail guides. These guides comprise a fixed dovetail formed in one side of the upper portion of the base while the other dovetail is adjustably provided by a spring loaded gib plate 24. This gib plate is disposed in a determined tension by a plurality of knurled-head setting screws 26. These screws, when desired, are tightened to clamp the plate 22 in a determined or selected position. A nut 28 is attached to and is carried on the underside of dovetail slide 22. This nut is movable in a recess 29 formed in base 20, said nut being engaged and moved by the rotation of screw 30 whose outer end portion is journaled in a hole in the base.

The slide 22 is attached to a dresser base 32 which is reciprocably moved by manipulation of knob 33 which is attached to and rotates screw 30 as the knob is turned. Mounted on base 32 is a center member 34 having a central recess formed therein to receive and retain a ball bearing 35. A like sized bore 36 is formed in dresser base 32, said bore disposed to retain a portion of the ball bearing. The base 32 and member 34 although shown as two separate components may, if desired, be made as a single unit.

The center member 34 has its outer diameter precisely sized and is positioned concentric to bore 36. A lower swivel ring 38 has its inner diameter sized so as to snugly engage and rotate on the exterior cylindrical surface of center member 34. A concentric cylindrical shouldered recess is formed in the upper half exterior portion of the lower swivel ring 38 and providing therein a bearing seat for slidably retaining in a rotational manner an upper swivel ring 39. As seen in FIGS. 1, 3 and 4, a stop 40 is carried on lower ring 38 and a like stop 41 is carried on upper ring 39.

As shown in FIG. 2, there is formed in the cylindrical surface of the center member 34 a radially disposed recess within which is carried a ball 43 urged outwardly by a spring 44. The outward thrust of the ball against the inner surface of the ring acts as a brake to restrain the ring 38 from rotation around center member 34. Formed in the upper portion of the member 34 is a channel or retaining groove in which is disposed a plurality of balls 46. These balls provide a ball bearing support for a swivel plate 47. This swivel plate 47 is retained in a precise rotational alignment with the member 34 by means of a vertically disposed shouldered shaft 48, the lower portion of which is carried in ball bearing 35. The internal portion of shaft 48 is threaded and is retained in bearing 35 by means of a screw 50, whose head engages a pair of spherical washers 51 and 52, which are tensioned to provide a determined spring-biased engagement and retention of the swivel plate 47 on the balls 46.

Carried by and attached to the dresser base and at the rear thereof is a vernier block 54 which is positioned on the base 32 so as to lie adjacent the outer cylindrical surface of the upper and lower swivel rings 38 and 39. Threadedly carried in block 54 is a knurled-head screw 56, whose inner end is disposed to engage the side of the upper swivel ring. As the screw is rotated inwardly the inner end thereof engages the upper ring 39 to deflect this ring inwardly against the lower ring 38 to lock both rings against the center member 34. In FIGS. 1 and 2 are seen indicia 57 precisely formed to relate to the degrees of rotation of swivel plate 47. This indicia may be read against a vernier inscription provided on the upper surface of vernier block 54. When screw 56 is in a disengaged relation to ring 39, the upper and lower rings are rotatable around center member 34.

The swivel plate 47 carries on its upper surface a pedestal portion 58 disposed to retain a diamond dressing tool 59 which may be mounted in either an upper or lower tool recess. The upper portion of this pedestal in this embodiment in- 5 cludes a lead weight 60 which is slidably carried in a recess 61 formed in an upper portion of the pedestal 58. This lead weight is supported by a spring 62 and is vertically retained within the formed recess by means of a cap 64. This weight acts as a dampener to reduce vibration which may be induced into the diamond tool 59 as it is traced across the face of a grinding wheel in the process of dressing' or "shaping" the wheel.

A pivoted upper portion 65 of the pedestal is carried on a shaft 68 rotatably mounted in a bearing 66. As thus pivotally supported, the upper portion 65 may be swung in an arc whose axis is at right angles to the axis of shaft 48. This horizontal bearing 66 is carried in pedestal 58 and serves as a positioning means for the shaft 68. This shaft is axially spring-biased leftwardly in the bearing by means of a screw 69, spring 70 and washer 71. As seen in FIGS. 1 and 2, a pair of pivoted upwardly extending horizontally spaced arms 72 include pin members 73 disposed to engage pedestal 5 8. These arms are spring-biased and the pins 73 engage the sides of pedestal 58 to urge the pivoted upper portion 65 into a vertical position. The upper pivoted portion may be swung from this vertical position around the shaft 68 by the manipulation of a lever arm 75. Arm 75 is carried on a hub portion 76 mounted on a shaft 77 having a crank arm engaging the pedestal 58 whereby in the rotation of shaft 77 the pivoted upper portion 65 is cammed either way from a normal vertical position as defined around the shaft 68.

As seen in FIG. 2 and FIG. 5, one embodiment ofa compensating means for the arc swing of upper portion 65 is provided. A pair of balls 80 is carried in a cage 82 on portion 65. As portion 65 is moved in relation to pedestal 58, these balls 80 are moved over a double convex surface 84 formed on the inner face of pedestal portion 58. The curved surfaces 84 are precisely calculated so that as upper portion 65 is rotated around shaft 68 the balls 80 will follow the curved surfaces 84 to cause the diamond tool 59 to not only swing in an arc around shaft 68 but also move inwardly or leftwardly at a predetermined rate as the upper portion 65 is moved away from the vertical position. The combination of these two arcs of movement is calculated to provide a precisely planer path for the diamond tool. The diamond tool will precisely dress a straight surface across the face of a grinding wheel.

As the amount of arc displacement is only a few ten thousandths of an inch, in many applications the wheel dresser is provided with surface 84 flat and parallel to the inner face of upper portion 65.

OPERATION OF THE DRESSER OF FIGS. 1 THROUGH 5 It is noted that in the above-described embodiment the wheel dresser is contemplated as mounted upon a grinder in the conventional manner. The operator, if he so desires, may loosen gib plate 24 and by rotating screw 30 by means of knob 33 move the dresser back and forth to precisely adjust and position the diamond in relation to the grinding wheel. After adjustment the gib is again tightened to lock slide 22. In use, usually only one of the diamond tools 59 is mounted in a tool support block 85. This block is movably mounted in a guideway formed in the pedestal 58 and after vertical adjustment the block is clamped in the guideway by means of a screw 86. The diamond is placed and clamped in either the upper or the lower retaining position as selected, after which the diamond dressing end is brought to the face of the grinding wheel in the customary manner. The arm 75, as it is manipulated to rotate shaft 77, causes the diamond to swing in an arc to dress the face of the diamond in a plane disposed at right angles to the shaft 68. When the tool dresser is to be used in this manner, it is contemplated that the knurled screw 56 has, prior to the rotation of the shaft 77, been turned inwardly to locally deflect the swivel rings 38 and 39 and effect a clamp of the upper and lower rings in a determined fixed position.

When it is desired to form an arcuate or curved surface on. the grinding wheel through the swinging of a diamond tool 59 around the shaft 48, the knurled screw 56 is rotated to move outwardly to permit the upper and lower rings 38 and 39 to move to an unconfined or free turning position whereupon the pedestal with the diamond tool thereon may be pivotally swung around the shaft 48. The ball 43 engages the inner diameter of the lower swivel ring 39 to act as a brake or drag upon the movement of this ring as used in the setting of the limits of movement of the pedestal as hereinafter is more fully described. As seen particularly in FIGS. 2, 3 and 7, there is carried on the swivel plate 47 a stop pin or block 90 which is attached to the swivel plate 47 by means of a screw 91. As seen particularly in FIG. 7, this stop pin has a pair of parallel threaded holes 92 and 93 disposed at right angles to the lon gitudinal axis of the block and at predetermined spacing. Set screws 94 and 95 are carried in holes 92 and 93 and are selectively movable by a socket head wrench, not shown. When the stop pin is in the attached condition, the screws 94 and 95 are disposed so as to engage the sides of the stops 40 and 41 of the upper and lower swivel rings as the stop pin is moved in way thereof.

, To adjust the degree of swing of the diamond 59, the screw 56 is brought to a disengaged condition so that the upper and lower swivel rings may be moved. The stops 40 and 41 are brought into engagement with stop pin 90, after which the swivel plate 47 and the attached stop pin 90 are swung in a clockwise direction as viewed in FIG. 1. As plate 47 is moved, the stop 40 is engaged and moved by the stop screw 95 to a determined limit of position. This limit of movement of the pedestal is read upon the vernier indicia 57 and the vernier block 54. After the stop 40 has been moved to its determined position to bring the swivel plate 47 to its one limit of position, the pedestal 58 is then swung in a counterclockwise direction, thereby moving swivel plate 47 and stop pin 90 in the opposite direction. Stop screw 94 engages the stop 41 and moves the upper swivel ring 39 to the other limit of movement which is also determined by the indicia 57 as read upon the vernier block 54.

It is to be noted that the brake or drag provided by the engagement of the spring-urged ball 43 against the inner surface of the lower swivel ring provides the means for the retaining of the lower swivel ring in its first set position while the upper swivel ring is being moved in an opposite direction to the other limiting position. After the upper and lower swivel rings have been moved to the determined position as shown by the vernier block 54, the knurled screw 56 is tightened against the upper ring 39 to cause the upper and lower rings to be locked against the center member 34. With the rings in the locked condition, the limits of movement of the pedestal are rechecked by reading the settings on the vernier. This original setting and locking of the rings may be considered a gross setting, whereas a precise limit setting is provided by adjusting the screws 94 and 95 which are turned in the stop pin block 90 to adjust the precise limit of movement of the swivel plate 47.. A lock stop 96, as seen in FIG. 3, is threadedly carried in swivel plate 47 and may be turned to engage the top surface of center member 34 to lock pedestal 58 at any position SETTING or THE DRESSER or FIGS. 1 ruaouon s Referring now to FIGS. 1, 2 and 3, it is to be noted that micrometer pins 97 and 98 are provided for thepre'cise setting of the diamond 59 in relation to the axisof shaft 48fPin 97 is precisely positioned a determined distance forwardly of the axis of shaft 48 and is carried by swivel plate47. Pin 98 is precisely positioned in and is carried in pedestal'58; The rear surface 99 of pivoted upper portion 65 is also a precise distance from the pin 98. l

The dresser may, by these pins 97 and 98 and surface 99, be precisely set for dressing a grinding wheel for either a convex or concave radius; for making a dead center facing or for dressing one or two angles.

To form a convex radius: (a) determine the micrometer reading from tip of diamond 59 to surface 99; (b) add the desired convex radius to the reading of step (a); (c) loosen gib plate 24 by loosening screws 25', (d) tuirn screw 30 by means of knob 33 until the outer surface of pins 97 and 98 are the exact distance of the sum of steps (a) and (b); (e) tighten gib 24 by tightening screws 25; (f) tool is now swung around shaft 48 by grasping hub 76. The tip of diamond tool 59 is at the precise radius back of shaft 48 as indicated at step (b).

To form a concave radius: (a) determine the micrometer reading from tip of diamond 59 to surface 99; (b) subtract the desired concave radius from the reading of step (a); (c) loosen gib plate 24 by loosening screws 25; (d) turn screw 30 by means of knob 33 until the outer surface of pins 97 and 98 are the exact computed distance of steps (a) and (b); (e) tighten gib 24 by tightening screws 25; (f) tool is now swung around shaft 48 by grasping hub 76. The tip of diamond tool 59 is now at the precise radius forward of shaft 48 as desired at step (b).

To form zero radius or dead center: (a) determine the micrometer reading from tip of diamond 59 to surface 99; (b) loosen gib plate 24 by loosening screws 25; (c) turn screw 30 by means of knob 33 until the outer surface of pins 97 and 98 are the exact distance of step (a); (d) tighten gib 24 by tightening screws 25.

To form one angle: (a) loosen knurled head screw 56; (b) grasp stops 40 and 41 and bring into position against stop pin 90; (c) move stops and stop pin to the desired angle by reading vernier at rear of swivel plate 47; (d) tighten knurled knob 56 to lock swivel rings at desired angle; (e) rotate lever arm to swing diamond 59in arc.

To obtain two angles: (a) loosen knurled head screw 56; (b) grip stops 40 and 41 against stop pin '90 and move lower swivel ring 38 clockwise to its desired vernier reading for the one desired angle; (c) swivel dresser and upper swivel ring in opposite or counterclockwise direction until the desired vernier reading for the upper swivel ring is obtained; ((1) tighten knurled knob 56 to lock upper and lower swivel rings at selected position for the two angles; move dresser to either of set positions and swing diamond through are by manipulating arm 75.

Combinations of dressing one angle and a radius or of two angles and radius, of course, may be provided by combining steps as outlined above.

The lock stop 96 (FIG. 3) is selectively used to retain the dresser at either of the set positions or at any other selected position.

ALTERNATE EMBODIMENT OF FIGS. 6 THROUGH 12 Referring next to FIG. 6, there is shown a wheel dresser similar to the dresser of FIG. 1. In this alternate embodiment only the upper portion of a dresser assembly is shown as this dresser is formed to also use the base 20, dovetail slide 22, gib plate 24, setting screws 25, nut 28 and screw 30 in the manner of the dresser as described above. In. this alternate embodiment a dresser base 132 is mountable upon the base 20 in the manner above-described; within this base there is provided a recess for a ball bearing 35 which rotatably carries the shaft 48 as above-described. A swivel plate 147 is substantially identical to the swivel plate 47 of FIG. 2 and carries the attached stop pin in the manner above-described. The base 132, instead of having a groove for carrying and retaining a plurality of balls 46, has the base formed with an upper surface 100 which is disposed to carry a multiplicity of balls 46. These balls are carried in a cage plate 102 which preferably retain the balls inan irregular pattern 50 that the balls avoid transcribing a path at a common radii'from. the axis of the shaft 48.

The irregular spacing of the balls reduces the possibility of the balls to form grooves the under surface of plate 147 and/or in the top surface 100 of the block 132. The plate is convoluted so as to be rotatably retained by the shaft 48 and to rest on surface 100 while nearly engaging the under surface of swivel plate 147. Apertures for balls 46 are formed in the plate 102 near the outer portion thereof, this portion being positioned midway between the surface 100 and plate 147.

It is to be noted that a lower swivel ring 138 is formed with upstanding ring portions projecting from both of its horizontal surfaces. The lower ring portion is sized to enter and engage the sides of a groove 104 in dresser base 132 and the upper ring portion -in a like manner enters a groove formed in an upper swivel ring 139. A like groove is formed in the upper surface of ring 139 so that the ring may be reversed, if desired. Similar grooves in ring 139 eliminate orienting problems at the time of assembly. It is also to be noted that lower ring 138 has its inner circumferential portion formed so as to provide a ring which extends upwardly into a mating groove formed in the bottom surface of the swivel plate 147. The plurality of radially disposed engaging surfaces provided between the base 132 and the upper and lower swivel rings 138, 139 and the swivel plate 147 provide aligning and thrust shoulders so that a concentricity of relationship of the mating parts is maintained during use and movement.

In this embodiment, a vernier plate 110 is attached to the upper surface of a vernier block 154 which threadedly carries a knurled screw 56 therein. A shoe member 112 is carried in a slot in block 154 and is movable inwardly so as to be brought into engagement with the upper and lower rings 138 and 139 to lock the two rings against rotation. This movement of shoe member 112 is in response to the thrust of the end of the screw when the screw 56 is turned inwardly. The pedestal 158 of this dresser has a fixed diamond retaining recess which is adapted to carry a diamond 59; however, this diamond is contemplated as being clamped from above by means of set screws 114 and 115. The pedestal also carries a thumb screw 118 which is adapted to move a lock block 120 into frictional engagement with pedestal 158 to lock the motion of a pivoted upper portion 165 at a determined position.

Referring particularly to FIG. 8, it is to be noted that arms 172 are urged toward each other by means of a spring 121. As the pivoted upper portion 165 is caused to swing about shaft 68 a compensating contour may be provided to allow the diamond 59 to be moved in and outwardly to compensate for the arc of movement.

Referring particularly to FIGS. 9, 10, 11 and 12, there is shown a compensating cam arrangement in which the pivoted upper portion 165 is provided with a pair of shoulder portions 122 and 123. These portions are disposed to rest upon like mating support surfaces 124 and 125 formed on member 158. Between the support surfaces 124 and 125 of member 158, there is formed a recess 127. In the pivoted upper portion 165, there are converging sloped cam portions 129 and 130 formed adjacent a relief 131.

As here shown, the support surfaces 124 and 125 are shaped and disposed so that as the pivoted upper portion is moved about shaft 68, the engagement with the oppositely disposed engaged portions 122 and 123 is displaced. Support surface 124 or 125 moves onto either sloped surfaces 129 or 130 and the pivoted upper portion 165 is moved inwardly toward the pedestal 153. The slopes 129 and 130 are shown in greatly exaggerated condition for the purposes of illustration. The amount of compensation necessary to adjust for the arc of the diamond 59 is provided by sloped surface 129 or 130 and as reduced to practice is only a few tenths of a thousandths of an inch. The slopes 129 and 130, therefore, are substantially parallel and planer with the shoulder surfaces 122 and 123. The radius of arc of the path of the diamond is readily determined and the compensation to be provided by slopes 129 and 130 is readily calculated.

It is, of course, recognized that the compensation arrangement of FIGS. 9, 10, 11 and 12 is a matter of election as the dresser of FIGS. 6 through 8 may be made with the facing surfaces of pedestal 158 and pivoted upper portion 165 disposed in parallel configuration. When so formed, the movement of the diamond 59 and the pivoted upper portion is in a determined plane.

OPERATION OF THE TOOL OF FIGS. 6 THROUGH 12 In the manner of the dresser of FIG. 1 described above, the wheel dresser of FIG. 6 is set and operated. For face and angle dressing, the screw 56 is turned to lock the set swivel rings 138 and 139 to base 132. To trace a curve around shaft 48, the screw 118 is manipulated to lock the pivoted portion 165 to the pedestal 158. The limits of the arc of movement or for setting angles the stop pin is used to set upper and lower swivel rings 138 and 139. After the gross adjustment has been made, a precise adjustment, where necessary, is made by adjusting screws 94 and 95.

In this embodiment the vibration dampener provided by the weight 60 of FIG. 1 is not shown. It is, of course, apparent that the pedestal 158 may be altered to provide this feature where desired.

The procedure for setting the dresser for tracing concave and convex curves and for angles is the same procedure as outlined above for the dresser of FIGS. 1 and 2.

Terms such as left, right, bottom, top, front", back, in, out, clockwise, counterclockwise and the like are applicable to the embodiments shown and described in conjunction with the drawings. These terms are used merely for the purposes of description and do not necessarily apply to the position in which the tool dresser may be constructed or used.

The conception of the tool dresser and the improvements therein and its many applications is not limited to the specific embodiments shown but departures therefrom may be made within the scope of the accompanying claims and without sacrificing its chief advantages and protection is sought to the broadest extent the prior art allows.

I claim:

1. A wheel dresser for precisely shaping grinding wheels and the like by means of a retained dressing point such as a diamond, said dresser including:

a. a base adapted for mounting on a grinding machine and the like;

b. a dresser base and center member movably mounted on the base;

c. a pair of nested swivel rings rotatably carried on the dresser base and center member, one of said swivel rings having a shouldered recess formed therein to provide a bearing seat for the other ring;

(I. a stop carried by each swivel ring and movable therewith;

e. a swivel plate disposed above the dresser base and swivel rings, said swivel plate carrying a pedestal and a dressing point retaining means;

f. a bearing carried in the dresser base and center member;

g. a vertically disposed shaft carried by the bearing and retained in the swivel plate so as to permit the swivel plate to be rotated around the axis of the shaft;

h. a stop pin carried by the swivel plate and disposed to lie between the stops carried by the swivel rings and to engage said stops to limit the movement of the swivel plate;

i. a plunger means carried by the dresser base and center member, the plunger means movable by a spring carried in the dresser base with the plunger means disposed to engage one of the swivel rings to restrain the rotative movements of said one swivel ring while the other swivel ring is being moved to a setting position; and

j. a locking means carried by the dresser base and disposed to be moved into engagement with at least one of the swivel rings to displace the rings into locking engagement with each other and the dresser base.

2. A wheel dresser as in claim 1 in which the dresser base and center member is carried in a dovetail guideway in the base, said base including at least one movable gib which may be adjusted so as to permit the dresser base to be reciprocated in the dovetail guideway. Said gib being also movable toward the other guideway to lock the dresser base in the base dovetail; and in which the swivel plate is carried by a plurality of like sized balls disposed between the under surface of the swivel plate and on a support surface formed on the dresser base and center member.

3. A wheel dresser as in claim 2 in which the balls are car ried in a cage plate retained by the vertical shaft and adapted for orientation with the swivel plate, the cage plate having a plurality of apertures disposed in an irregular pattern to retain the balls in said pattern so that the balls transcribe paths having dissimilar radii in respect to the axis of rotation of the swivel plate.

4. A wheel dresser as in claim 1 in which the plunger means is a ball urged by the spring against the inner surface of the lower of the swivel rings; and in which the shouldered recess in the lower swivel ring is a circular cutout formed in the upper outer portion of the lower swivel ring; and in which the stop pin is provided with a pair of adjusting screws disposed in spaced parallel threaded passageways in the stop pin and with each of the stops on the swivel rings disposed to engage on the adjusting screws.

5. A wheel dresser as in claim 1 in which the pedestal includes a pivoted upper portion, said upper portion having a guideway in which is movably retained a tool support block containing the dressing point retaining means, said pedestal and pivoted upper portion having in one of said members a recess formed to slidably retain a dampening weight, and a dampening weight in said recess, the weight resiliently supported and retained in the recess by a recess closing member.

6. A wheel dresser as in claim 1 in which the swivel plate is provided with indicia representing degrees of rotation; and in which the locking means includes a vernier block attached to the dresser base and center member, and in which the vernier block carried a screw having one end disposed to engage the upper of the swivel rings to deflect the swivel rings into a frictional lock with each other and with the center member.

7. A wheel dresser as in claim 1 in which the swivel plate is provided with indicia representing degrees of rotation; and in which the locking means includes a vernier block attached to the dresser base and center, the vernier block having a guideway formed adjacent the upper and lower swivel rings, a shoe member carried in this guideway; and ascrew carried in a threaded hole in the vernier block, the screw adapted to engage the shoe member and the shoe member to engage and lock the swivel rings against rotation.

8. A wheel dresser as in claim 1 in which the pedestal is provided with a pivoted upper portion, a lever disposed to move the pivoted upper portion in an oscillatory manner; the pedestal and pivoted upper portion being urged toward each other by means of a spring to bring mating faces of the pedestal and pivoted upper portion into sliding engagement,

and a cam means formed on one of the faces to cause the tool tracing point carried in the pivoted upper portion to move in a compensated path across the medium [being dressed.

9. A wheel dresser as in claim 8 in which one of the mating faces is provided with two shoulder portions disposed a determined distance apart, and in which the other mating face is provided with a pair of support surfaces of determined width each disposed to rest upon a facing shoulder portions when the pivoted upper portion is in a neutral attitude, and in which there is provided converging cam portions formed adjacent the support surfaces, the converging cam portions having a slope equal to the amount of compensation desired in the swing of the pivoted portion.

10. A wheel dresser as in claim 1 in which the pedestal is provided with a pivoted upper portion and a lever disposed to move the pivoted upper portion in an oscillatory manner, the pedestal and pivoted upper portion being urged toward each other by means of a spring; a pair of spaced-apart facing surfaces precisely formed on the pedestal and pivoted upper portion; at least two balls carried in a cage, said balls disposed between the spaced-apart facing surfaces and sized so as to maintain the surfaces at a determined distance from each other, and a cam contour formed on one of the facing surfaces and engaging the balls so as to cause the tool tracing point carried in the pivoted upper portion to move in a compensated path across the medium being dressed.

11. A wheel dresser as in claim 1 in which the axis of the rotation of the swivel plate coincides with the axis of rotation of the swivel rings an in which the dresser base and center,

the swivel rings and the swivel plate are formed with engaging ring and groove portions disposed to provide radial engaging shoulders to assist the vertical shaft in maintaining concentricity of movement.

12. A wheel dresser as in claim 1 in. which there is provided a micrometer pin on the swivel plate, the pin disposed a determined distance forwardly of the axis of the vertical shaft, and in which a second micrometer pin is provided in the pedestal, said second micrometer pin being a determined distance forwardly of the rear surface of a pivoted upper portion carried by the pedestal whereby the precise measuring of the distance from the rear surface of the upper portion to the point of the dressing tool may be determined and by manipulating the distance over the micrometer pins a desired position of the point of the dressing tool to the axis of the vertical shaft may be adjustably provided. 

